In order to allow for user interaction with a display device, inductive, resistive or capacitive sensors may be integrated into the display device. However, inductive sensors are often too expensive for large displays while resistive and capacitive sensors generally do not provide sufficient resolution for more complex functions such as handwriting capture or graphic design.
Other techniques for user interaction with the display device include applying an optical pattern to a surface of the display device with an optical reader type stylus being used by the user to detect this pattern. Current patterns are usually formed from an infrared (IR) reflecting ink that reflects IR light projected by the stylus. The stylus detects the pattern based on contrast between the reflected IR light and non-reflected IR light. However, such contrast may be difficult to detect on glass or plastic surfaces of the display devices. Moreover, these patterns may degrade image quality of the display device due to these patterns blocking some visible light being emitted from the surface of the display device.